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Our colour shops are said to be supplied with this usefulearth from Italy and Germany j though some parts ofEngland afford substances, nearly, if not entirely, of thesame quality, and which are found to be equally service-able, both for marking and as black paints. Such parti-cularly is the black earthy substance called Killow; said byDr. Merrett, in his Pinax rerum Britannicarum , to be foundin Lancashire; and by Mr. Da Costa, in his history of fos-sils, to be plentiful on the side, near the top, of Cay-A von,an high hill in Merionethshire. The killow has some-what of a bluish or purplish cast mixed with its blackness,as the black chalk likewise has: hence it is named byMerrett blue marking stone, lapis cæruleus killow diet usducendis lineis idoneus. There is a harder and softer kindof it, killoia duriufcula £t molliujcula of Woodward’s me-thod of fossils.

II. Pit coal.

From the deep glossy black colour of some of the com-mon sorts of pitcoal, I was induced to make trial of themas paints : their affinity to oils, in virtue of their bitumi-nous nature, promised also some advantages, in oil paint-ing, above the substances of a more earthy kind. Severalof the finer pieces, levigated into an impalpable powder,were mixed both with oil and with gum water, and appliedon paper and on wood. Both mixtures, when laid on thick,appeared of a pretty good black colour, though much in-ferior to that of the coal at first; and the oily one seemedto dry sooner than oil paints generally do. Laid on thin,or in a dilute state, they looked brown, not of the greycolour which results from the dilution of a pure black.Pitcoal therefore may be considered, not as a true black,but as a brown-black; a colour on many occasions wantedin painting, and which, as I have been informed by an in-genious